Stand Volume Equation Developed from an Experimental Form Factor with the Breast Height Form Quotient

實驗形數是樹高材積與樹高加3（K項）乘以胸高斷面積的比值。實驗形數法是基於各樹種平均實驗形數來估算林分蓄積的重要方法。實驗形數法考慮了林木形狀，使得估算林分蓄積更準確簡易。試驗地位於中國吉林省長白山區天然雲冷杉混交林14塊皆伐標準地，建立了該地區的實驗形數林分蓄積方程，並且與該地區二元材積表估計林分蓄積的精度進行比較。結果顯示：相較於二元材積表，實驗形數林分蓄積方程有更小的平方差，更高的預估精度和擬合度。通過T檢驗和F檢驗，實驗形數林分蓄積方程估算值與分析解析木樣地蓄積值很接近，在統計上無顥著差異。本文第一次從樹種胸高形率和樹幹曲線方程理論推倒出實驗形數方程。與經典經驗實驗形數算法相比，本文推算11個樹種的實驗形數差別不大。實驗形數也第一次被證明只受到不同樹種的影響，常數項K平均積為3.3（變異係數為0.02）。

關鍵字

實驗形數；胸高形率；林分蓄積；樹高級

並列摘要

The experimental form factor (EFF) is the ratio of tree volume to the volume of a cylinder that has the same diameter at breast height and is 3 m (K) higher than the tree, which is an important method to estimate stand volume. To estimate the stand volume more accurately and simply, the proposed approach considered form factors. Based on 14 clear-cut sample plots of spruce-fir mixed stands at Changbai Mountains, Jilin, China, an EFF stand volume formula was established using mathematical deduction and was weighed against the estimating precision by a 2-entry table method. The results demonstrated that the model had a smaller deviation, and better prediction precision and goodness of fit by applying the EFF formula than the 2-entry table formula. Through an independent-samples t-test and F test, no significant differences were observed between the real stand volume and the stand volume estimated by the EFF formula. The EFF volume formula was first deduced from the theoretical stem curve formula with the breast height form quotient (BFQ). In a comparison of results obtained by the classical approach, EFF values for 11 species applying the theoretical derivation marginally differed. The EFF was verified to be affected only by species. Item K was certified to be constant term with a coefficient of variance of 0.02.

並列關鍵字

experimental form factor ； breast height form quotient ； stand volume ； height class

國際替代計量

Stand Volume Equation Developed from an Experimental Form Factor with the Breast Height Form Quotient

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